This made me check my gliding log book - at 60 solo hours I had flown 7 types solo, and 6 dual.
Admittedly, if there was a type I hadn't flown available I'd try to get a flight in it, so I might be atypical. However, I'm very far from being a hot shot pilot.
I think it did my flying a lot of good, as did flying from unfamiliar airfields. I guess a lot depends on your confidence levels - I took the view that these aircraft were all flown from these airfield by pilots with similar levels of experience to mine, so there would be nothing I shouldn't be able to cope with.
I can't translate this to powered flying because I have a grand total of about 40 mins (Tiger Moth - taxying, takeoff, handling and stalls no problem, ditto approach and roundout but the flare was so far from what I was used to that the instructor did that because he got bored with waiting for me). Fellow type collectors can probably enlighten you here.
For what it's worth, I found that if the aircraft did the same things but in a different way, then I could cope with concentration. Aircraft which added complexity required more experience, such as my current glider which has a tail parachute.
Why not ask an instructor with whom you've flown recently? If he/she thinks you can cope on that type, trust that judgment.
PS In the 250 hrs since then I've only added another 10 or so types - if anyone has an unusual glider I can fly, let me know!